A technique is known that a snap shot image of a database using a memory (e.g. in-memory database) is saved in a disk against occurrences of any troubles or the like. However, when a capacity of the memory becomes large, it takes a long time to save the snapshot into the disk. Therefore, the operation of the system may be stopped. Moreover, because it also takes a long time to restore the snap shot from the disk to the memory when any trouble actually occurs, the recovery of the state of the system may be delayed.
Moreover, there is a technique for saving backup data of data on a disk onto another disk. However, the state of the system (e.g. a state of a processor) cannot be recovered only by backing up the data on the disk.
In addition, there is a technique for duplicating the memory, separating one memory when any fault occurs, and gathering damp data from the separated memory. However, an object of this technique is to gather the damp data, and this technique cannot recover the state of the system.